22,692 research outputs found

    Shuttle system ascent aerodynamic and plume heating

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    The shuttle program provided a challenge to the aerothermodynamicist due to the complexity of the flow field around the vehicle during ascent, since the configuration causes multiple shock interactions between the elements. Wind tunnel tests provided data for the prediction of the ascent design heating environment which involves both plume and aerodynamic heating phenomena. The approach for the heating methodology based on ground test firings and the use of the wind tunnel data to formulate the math models is discussed

    Water resource records of the Econfina Creek Basin area, Florida

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    The Econfina Creek basin area in northwestern Florida, which includes Bay County, southeastern Washiigton County, and parts of Calhoun, Gulf, and Jackson counties is shown in figure 1. The basin has an abundant supply of ground water and surface water of good quality. This determination is based on a three-year investigation of the water resources of the basin by the U. S. Geological Survey in cooperation with the Division of Geology, Florida Board of Conservation, during the period from October 1961 through June 1964. The purpose of this report is to assemble the basic data collected during this investigation for those persons interested in water development or management in this basin. (Document has 131 pages.

    Determination of Frequency and Distribution of Hessian Fly (Diptera: Cecidomyiidae) Biotypes in the Northeastern Soft Wheat Region

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    Fifteen collections of Hessian flies from the northern soft winter wheat region of the United States were used to determine the composition and frequency of biotypes. The wheat cultivars \u27Seneca\u27 (H7Hs), \u27Monon\u27 (H3), \u27Knox 62\u27 (~, H7Hg), and \u27Abe\u27 (Hs) were used as differentials. Biotypes J and L replaced biotype B as the prevalent biotype in Indiana, since wheat cultivars having the Hs and the H6 genes have been grown. Biotype GP, the least virulent of any Hessian fly biotypes, was still present in New York indicating that wheat cuItivars with no genes for resistance are still being grown there. The genetic variability of Hessian fly biotypes that enables them to overcome the resistance in wheat cultivars is discussed

    Preschoolers\u27 Strategies Used to Delay Gratification

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    A study to explore the use of orbital remote sensing to determine native arid plant distribution

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    The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate

    Snow water equivalent determination by microwave radiometry

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    One of the most important parameters for accurate snowmelt runoff prediction is snow water equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the microwave radiation

    Visual tracking of a GPS target within a FieldLab

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    The monitoring and videoing of a user’s movement within a “FieldLab” recreational facility is required to study the effectiveness of innovative equipment designed to increase physical activity. A low cost alternative to current tracking systems based around the Global positioning system (GPS) was trialed for use within the Sheffield FieldLab. This low cost tracking system is based around a typical AndroidTM smartphone, which was used as a wearable tracking sensor. The system was combined with a bespoke video surveillance system, which takes positional data and outputs appropriate camera parameters. In pilot work, participants’ GPS positional data was converted in real time to a pan tilt and zoom value. This allowed the targeted participant to be viewed in the centre of the video stream. Positional data was updated every second, allowing the camera to move and track the participant by keeping them at the centre of the video frame as they moved around the site. The effectiveness of the system was gauged and limitations noted. It was found that the Sony Xperia-S gave the most accurate GPS positional data, out of the three smartphones tested in this study. Other potential uses as well as enhancements to the system have also been commented on

    Hex ball torque test

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    A series of torque tests were performed on four flight-type hex ball universal joints in order to characterize and determine the actual load-carrying capability of this device. The universal joint is a part of manual actuation rods for scientific instruments within the Hubble Space Telescope. It was found that the hex ball will bind slightly during the initial load application. This binding did not affect the function of the universal joint, and the units would wear-in after a few additional loading cycles. The torsional yield load was approximately 50 ft-lb, and was consistent among the four test specimens. Also, the torque required to cause complete failure exceeded 80 ft-lb. It is concluded that the hex ball universal joint is suitable for its intended applications

    Effect of heuristics on serendipity in path-based storytelling with linked data

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    Path-based storytelling with Linked Data on the Web provides users the ability to discover concepts in an entertaining and educational way. Given a query context, many state-of-the-art pathfinding approaches aim at telling a story that coincides with the user's expectations by investigating paths over Linked Data on the Web. By taking into account serendipity in storytelling, we aim at improving and tailoring existing approaches towards better fitting user expectations so that users are able to discover interesting knowledge without feeling unsure or even lost in the story facts. To this end, we propose to optimize the link estimation between - and the selection of facts in a story by increasing the consistency and relevancy of links between facts through additional domain delineation and refinement steps. In order to address multiple aspects of serendipity, we propose and investigate combinations of weights and heuristics in paths forming the essential building blocks for each story. Our experimental findings with stories based on DBpedia indicate the improvements when applying the optimized algorithm
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